And then there were the odd song choices; they played a little something called "Scumbag," another little something called "Jamrag" and an actual song, Walter Ward's bluesy "Well (Baby Please Don't Go)," which featured Lennon on vocals and Zappa on lead guitar. It was the highlight of the jam, for sure.

"For those of you in the band who have no idea what's about to happen, this is in A minor, and it's not standard blues changes," Zappa says as he introduces "Well (Baby Please Don't Go)." "But it's close." "This is a song I used to sing when I was at the Cavern in Liverpool," Lennon adds. "I haven't done it since."

Zappa's powerful guitar solo starts at 2:05.

If you happen to enjoy what you hear, the performance was released as part of Lennon and Ono's poorly received (and not very good at all) 1972 studio/live album, Sometime in New York City. That said, it's cool to see Lennon—who was back to his 1967-length hair at this point—having fun onstage with his Gibson SG, standing, acting and looking very much like "Beatle John." Enjoy!